The invention generally relates to superconductive compounds and, in particular, high temperature superconductive compounds exhibiting both a superconductive state and a resistive state, the particular state in which the compounds exist being controllable, such as by the application of either transient current pulses or magnetic field pulses to the compounds.
Switching devices are well known in the prior art. For example, a Josephson junction device is a structure formed of two (usually thin film) superconductors separated, in all cases, by a very thin (less than a millionth of an inch) insulator. This device shows a nonlinear and hysteretic current-voltage behavior which can be used for switching small amounts of current, and storing information with small amounts of energy. It also exhibits great sensitivity to magnetic fields. These devices are currently used in commercially available equipment to measure weak magnetic fields (where they exceed all other devices in sensitivity), and in experimental prototypes of new, high speed computers.
There is a need for a structure of monolithic superconducting material, such as a rod or patterned thin film path, which can be caused to exhibit switching, storage, and erasure effects. There is also a need for a switching device which differs from the Josephson junction device in structure and area of application. Regarding structure, there is a need for a switching device which avoids the need for insulators and microscopic dimensions. Regarding area of application, there is a need for a switching device having a low electrical impedance which can be controlled by varying length and cross sectional area so that such a device can be utilized to carry large amounts of current or utilized to present very small electrical impedances.
There is also a need for a process for the production of a superconducting material which can be changed from a superconductive state to a resistive state.